Scalable fabrication of amorphous silicon anode electrodes for battery cells

Abstract

The invention relates to scalable fabrication of amorphous silicon anode electrodes for battery cells. A method for manufacturing an anode electrode of a battery cell includes supplying a roughened anode current collector from a roll-to-roll chamber to a magnetron sputtering chamber; traveling the roughened anode current collector around a roller in a magnetron sputtering chamber; sputtering an amorphous silicon layer on the roughened anode current collector to form an anode electrode using T sputtering targets arranged circumferentially around a portion of the roll, where T is an integer greater than 1; and receiving an anode electrode from the magnetron sputtering chamber at the roll-to-roll chamber.

Description

Technical Field

[0001] The present disclosure relates to battery cells of a battery pack, and more particularly to an anode electrode and a method for manufacturing an anode electrode of a battery cell of a battery pack. Background Art

[0002] The information provided in this section is for a general introduction to the background of the present disclosure. The work of the currently named inventors described in this section, and aspects of the specification that may not be determined as prior art in other forms at the time of filing, are not expressly or implicitly admitted as prior art to the present disclosure.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles include one or more electric motors and a battery pack system including one or more battery cells, modules, and / or packs. A power control system is used to control charging and / or discharging of the battery pack system during charging and / or driving.

[0004] A battery cell includes a cathode electrode, an anode electrode, and a separator. The cathode electrode includes a cathode active material layer disposed on a cathode current collector. The anode electrode includes an anode active material layer disposed on an anode current collector. Summary of the Invention

[0005] A method for manufacturing an anode electrode of a battery cell of a battery pack includes supplying a roughened anode current collector from a roll-to-roll chamber to a magnetron sputtering chamber; causing the roughened anode current collector to travel around a roller in the magnetron sputtering chamber; sputtering an amorphous silicon layer on the roughened anode current collector using T sputtering targets circumferentially disposed around a portion of the roller to form an anode electrode, where T is an integer greater than 1; and receiving the anode electrode from the magnetron sputtering chamber in the roll-to-roll chamber.

[0006] In other features, the roughened anode current collector is made of a material selected from copper, stainless steel (SS), nickel (Ni), titanium (Ti), and tin (Sb). The roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm. The thickness of the roughened anode current collector is from 0.1 μm to 40 μm. The thickness of the amorphous silicon layer is from 0.1 μm to 20 μm.

[0007] In other features, the amorphous silicon layer includes a plurality of silicon pillars. The diameter of the plurality of silicon pillars is from 0.1 μm to 15 μm. The average areal capacity of the anode electrode is 4 to 30 mAh / cm 2 。

[0008] Among other features, the DC bias voltage of the magnetron sputtering chamber is from 100 V to 1000 V. The cathode power of the magnetron sputtering chamber is from 0.5 kW to 30 kW.

[0009] The battery pack cell includes A anode electrodes, wherein each of the A anode electrodes includes a roughened anode current collector. The anode active material layer includes an amorphous silicon layer deposited on the roughened anode current collector using physical vapor deposition (PVD). The C cathode electrodes include a cathode current collector and a cathode active material layer disposed on the cathode current collector. The battery pack cell includes S separators, wherein A, C, and S are integers greater than 1.

[0010] Among other features, the roughened anode current collector is made of a material selected from copper, stainless steel (SS), nickel (Ni), titanium (Ti), and tin (Sb). The roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm. The thickness of the roughened anode current collector is from 0.1 μm to 40 μm. The thickness of the amorphous silicon layer on the roughened anode current collector is from 0.1 μm to 20 μm. The amorphous silicon layer includes a plurality of silicon pillars.

[0011] Among other features, the diameter of the plurality of silicon pillars is from 0.1 μm to 15 μm. The average areal capacity is 4 to 30 mAh / cm 2 。

[0012] The system for manufacturing the anode electrode of a battery pack cell includes a roll-to-roll chamber and a magnetron chamber. The magnetron chamber includes a roller and T sputtering targets circumferentially arranged around a part of the roller, wherein T is an integer greater than 1. The roll-to-roll chamber supplies the roughened anode current collector to the magnetron sputtering chamber. The roughened anode current collector travels around the roller in the magnetron sputtering chamber. The T sputtering targets sputter an amorphous silicon layer on the roughened anode current collector to form the anode electrode. The anode electrode travels from the magnetron sputtering chamber to the roll-to-roll chamber.

[0013] The present invention discloses the following solutions:

[0014] Solution 1. A method for manufacturing an anode electrode of a battery pack cell, which includes:

[0015] Supplying a roughened anode current collector from a roll-to-roll chamber to a magnetron sputtering chamber;

[0016] Making the roughened anode current collector travel around the roller in the magnetron sputtering chamber;

[0017] Using T sputtering targets circumferentially arranged around a part of the roller to sputter an amorphous silicon layer on the roughened anode current collector to form the anode electrode, wherein T is an integer greater than 1; and

[0018] Receive an anode electrode from the magnetron sputtering chamber in the roll-to-roll chamber.

[0019] Solution 2. The method according to Solution 1, wherein the roughened anode current collector is made of a material selected from copper, stainless steel (SS), nickel (Ni), titanium (Ti), and tin (Sb).

[0020] Solution 3. The method according to Solution 1, wherein the roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm.

[0021] Solution 4. The method according to Solution 1, wherein the thickness of the roughened anode current collector is from 0.1 μm to 40 μm.

[0022] Solution 5. The method according to Solution 1, wherein the thickness of the amorphous silicon layer is from 0.1 μm to 20 μm.

[0023] Solution 6. The method according to Solution 1, wherein the amorphous silicon layer comprises a plurality of silicon pillars.

[0024] Solution 7. The method according to Solution 6, wherein the diameter of the plurality of silicon pillars is from 0.1 μm to 15 μm.

[0025] Solution 8. The method according to Solution 1, wherein the average areal capacity of the anode electrode is 4 to 30 mAh / cm 2 .

[0026] Solution 9. The method according to Solution 1, wherein the DC bias voltage of the magnetron sputtering chamber is from 100 V to 1000 V.

[0027] Solution 10. The method according to Solution 1, wherein the cathode power of the magnetron sputtering chamber is from 0.5 kW to 30 kW.

[0028] Solution 11. A battery pack cell, comprising:

[0029] A anode electrodes, wherein each of the A anode electrodes comprises:

[0030] A roughened anode current collector; and

[0031] An anode active material layer comprising an amorphous silicon layer deposited on the roughened anode current collector using physical vapor deposition (PVD);

[0032] C cathode electrodes, comprising a cathode current collector and a cathode active material layer disposed on the cathode current collector; and

[0033] S separators, wherein A, C, and S are integers greater than 1.

[0034] Embodiment 12. The battery cell of the battery pack according to Embodiment 11, wherein the roughened anode current collector is made of a material selected from copper, stainless steel (SS), nickel (Ni), titanium (Ti), and tin (Sb).

[0035] Embodiment 13. The battery cell of the battery pack according to Embodiment 11, wherein the roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm.

[0036] Embodiment 14. The battery cell of the battery pack according to Embodiment 11, wherein the thickness of the roughened anode current collector is from 0.1 μm to 40 μm.

[0037] Embodiment 15. The battery cell of the battery pack according to Embodiment 11, wherein the thickness of the amorphous silicon layer on the roughened anode current collector is from 0.1 μm to 20 μm.

[0038] Embodiment 16. The battery cell of the battery pack according to Embodiment 11, wherein the amorphous silicon layer includes a plurality of silicon pillars.

[0039] Embodiment 17. The battery cell of the battery pack according to Embodiment 16, wherein the diameter of the plurality of silicon pillars is from 0.1 μm to 15 μm.

[0040] Embodiment 18. The battery cell of the battery pack according to Embodiment 11, wherein the average areal capacity is from 4 to 30 mAh / cm 2 .

[0041] Embodiment 19. A system for manufacturing an anode electrode of a battery cell of a battery pack, comprising:

[0042] A roll-to-roll chamber;

[0043] A magnetron chamber including a roll and T sputtering targets circumferentially arranged around a part of the roll, where T is an integer greater than 1,

[0044] wherein the roll-to-roll chamber supplies a roughened anode current collector to the magnetron sputtering chamber;

[0045] wherein the roughened anode current collector travels around the roll in the magnetron sputtering chamber, and the T sputtering targets sputter an amorphous silicon layer onto the roughened anode current collector to form an anode electrode.

[0046] Further applicable fields of the present disclosure will be apparent from the detailed description, the claims, and the drawings. The detailed description and the specific embodiments are only for illustration purposes and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present disclosure will be more fully understood from the detailed description and the accompanying drawings, wherein:

[0048] Figure 1 is a side cross-sectional view of an example of a battery cell of a battery pack including A anode electrodes, C cathode electrodes, and S separators according to the present disclosure;

[0049] Figure 2A is a side cross-sectional view of an example of a roughened current collector and an amorphous silicon layer PVD-deposited on the current collector according to the present disclosure;

[0050] Figure 2B is a plan view of an example of a roughened current collector and an amorphous silicon layer PVD-deposited on the current collector according to the present disclosure;

[0051] Figure 3 is a functional block diagram of an example of a magnetron for depositing amorphous silicon on a roughened current collector;

[0052] Figure 4 is a functional block diagram of an example of a magnetron for depositing amorphous silicon on a roughened current collector using multiple targets in a roll-to-roll method according to the present disclosure;

[0053] Figure 5A and 5B show an example of an anode electrode during charging and discharging according to the present disclosure;

[0054] Figure 6 is a side cross-sectional view of an example of a battery cell of a battery pack including an anode electrode having a liquid electrolyte according to the present disclosure;

[0055] Figure 7 is a side cross-sectional view of an example of a battery cell of a battery pack including an anode electrode having a solid electrolyte according to the present disclosure;

[0056] Figure 8 is an example of a scanning electron microscope image of a top view and a side view of an anode electrode according to the present disclosure;

[0057] Figure 9A and 9B are examples of an X-ray diffraction (XRD) pattern and a Raman spectrum of an anode electrode according to the present disclosure, respectively; and

[0058] Figure 10A and 10B are graphs showing examples of the capacity and the capacity retention percentage of an anode electrode as a function of the number of cycles according to the present disclosure, respectively.

[0059] In the drawings, reference numerals may be reused to designate similar and / or identical elements. Detailed Description

[0060] Although the battery cell according to the present disclosure is shown in the context of an electric vehicle, the battery cell can be used in stationary applications and / or other applications.

[0061] Due to multiple lithium ion (Li + ) diffusion paths and high theoretical capacity, silicon is a promising candidate for anode active material. Developing high-performance flake silicon anodes is important for constructing practical lithium-ion battery packs. Typically, flake silicon anodes are manufactured using wet coating methods. However, the delivered rate capability and cycling of the anode electrode still need to be enhanced.

[0062] The present disclosure relates to a method for manufacturing an anode electrode that includes an amorphous silicon anode layer (e.g., including silicon pillars) deposited on a roughened copper current collector. The anode electrode can be produced using a scalable roll-to-roll manufacturing method.

[0063] Conventional wet coating methods mix an anode active material, a conductive additive, a binder, and a solvent into a mixture. The mixture is cast onto an anode current collector and then a drying stage is used to remove the solvent. The solvent has environmental issues and the drying stage increases the footprint of the method.

[0064] The method for manufacturing the anode electrode according to the present disclosure uses magnetron sputtering. This method eliminates the use of binders, conductive additives, and solvents, which simplifies the manufacturing method of the silicon anode while increasing the energy density. In addition, the amorphous silicon layer includes a concavo-convex surface. The concavo-convex surface can have more contact interfaces with the electrolyte to increase the lithium ion conduction paths and help release stress during the volume change of silicon during cycling.

[0065] Now referring to Figure 1 , the battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in a battery cell stack 12, where C, S, and A are integers greater than zero. The battery cell stack 12 is disposed in a housing 50. The C cathode electrodes 20-1, 20-2,..., and 20-C include cathode active material layers 24 disposed on one or both sides of a cathode current collector 26. The A anode electrodes 40-1, 40-2,..., and 40-A include anode active material layers 42 disposed on an anode current collector 46. In some instances, the A anode electrodes 40 and the C cathode electrodes 20 exchange lithium ions during charging / discharging.

[0066] In some instances, the anode active material layer 42 includes a silicon layer deposited by PVD on the anode current collector 46. The anode current collector 46 includes a roughened current collector. In some instances, the cathode active material layer 24 includes a coating that includes one or more active materials, one or more conductive additives, and / or one or more binder materials applied (cast or laminated) on the current collector.

[0067] In some instances, the cathode current collector 26 includes a metal foil, a metal mesh, a perforated metal, a three-dimensional (3D) metal foam, and / or an expanded metal plate. In some instances, the cathode current collector is made of one or more materials selected from stainless steel, brass, bronze, zinc, and aluminum. The external tabs 28 and 48 are connected to the current collectors of the cathode electrode and the anode electrode, respectively, and may be disposed on the same side or different sides of the battery module stack 12. The external tabs 28 and 48 are connected to the terminals of the battery module cells.

[0068] In some instances, the battery module cell 10 uses a liquid electrolyte 52. In other instances, a solid-solid electrolyte, a gel electrolyte, and / or a liquid electrolyte are used.

[0069] Now referring Figure 2A and 2B , one of the A anode electrodes 40 is shown in further detail. In Figure 2A , one of the A anode electrodes 40 includes an anode current collector 46 and an anode active material layer 42. In some instances, the anode current collector 46 includes a roughened surface 47 on its opposite sides. The anode active material layer 42 includes an amorphous silicon layer 60 deposited using physical vapor deposition (PVD). The Si morphology will depend on the bias DC voltage and / or the silicon cathode power during the roll-to-roll manufacturing process.

[0070] When the DC voltage is 100 to 500 V (e.g., 350 - 500 V) and / or the cathode power is 0.5 to 12 kW (e.g., 10 kW), silicon is deposited evenly and gently on the roughened current collector to form silicon pillars including convex spherical surfaces. In some instances, the height (e.g., H S1 ≈H S2 ≈H Sn ) of the amorphous silicon layer on the roughened anode current collector is 0.1 μm to 20 μm. In some instances, the diameter (e.g., D S1 ≈D S2 ≈D Sn ) of the silicon pillars is 0.1 μm to 15 μm. In some instances, the average areal capacity is 4 to 30 mAh / cm 2 (e.g., 10 to 20 mAh / cm for both sides 2 ).

[0071] In some instances, the roughened anode current collector includes a roughened surface to achieve a tight interface with the amorphous silicon layer. In some instances, the roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm (e.g., 8 μm). In some instances, the thickness of the roughened anode current collector (e.g., H C1 、H C2 、H Cn ) is from 0.1 μm to 40 μm. In some instances, the roughened anode current collector is made of a material selected from copper, stainless steel, nickel (Ni), titanium (Ti), and tin (Sn).

[0072] Reference is now made to Figure 3 and Figure 4 , the description of a static DC magnetron sputtering apparatus ( Figure 3 ) will be used to assist in explaining a continuous DC magnetron sputtering apparatus ( Figure 4 ) for continuously producing an anode electrode according to the present disclosure. In Figure 3 , the DC magnetron sputtering apparatus 200 deposits an anode active material layer containing amorphous silicon on the roughened anode current collector 46. The roughened anode current collector 46 is disposed on a substrate support 214 in a processing chamber 210. A magnetron cathode 216 including a magnet 220 and a target 218 is disposed spaced apart from the substrate support 214.

[0073] During deposition, a process gas mixture such as argon (Ar) from a gas source 222 is introduced into the processing chamber 210 while supplying AC and / or DC power. In some instances, a mass flow controller 224 and a valve 226 are used to meter the process gas entering the processing chamber 210 from the gas source 222. A throttle valve 234 and / or a pump 238 control the pressure within the processing chamber 210 and / or the discharge of reactants from the processing chamber 210. A DC power supply 244 supplies a DC voltage to the magnetron cathode 216. An AC power supply 246 supplies an AC voltage to the magnetron cathode 216.

[0074] During deposition, target material (e.g., silicon) is ejected from the target 218 and deposited on the roughened anode current collector 46. Material is also sputtered from the exposed surface of the roughened anode current collector 46. In some instances, a silicon target (e.g., n-type; 99.995%) sputters silicon particles onto a porous anode current collector (e.g., copper mesh). In some instances, the DC source 244 supplies a DC voltage of 100 V to 1000 V. In some instances, the cathode power from the AC source 246 is 0.5 to 30 kW and the frequency is 20 to 200 kHz. In some instances, the width of the current collector is 10 to 500 cm. In some instances, the method can be performed two or more times on the same side to increase the thickness of the amorphous silicon layer.

[0075] In some instances, sputtering is performed on a continuous current collector in a roll-to-roll method. The speed of the roll-to-roll method is from 2 m / min to 20 m / min. In some instances, the width of the anode current collector is from 10 cm to 500 cm. Since this is a solvent-free manufacturing method, environmental control of solvent use or a drying stage to remove solvent is not required. The anode electrode has good mechanical flexibility, which increases durability.

[0076] Now refer to Figure 4 , the continuous DC magnetron sputtering apparatus 300 uses multiple targets to deposit amorphous silicon PVD on a roughened current collector in a roll-to-roll method. The roll-to-roll chamber 310 houses a roller 314 that supplies the roughened current collector 312. The roughened current collector 312 is fed around a roller 316, around tension rollers 318 and 322, and passes through an elongated hole 325 (e.g., acting as a vacuum seal) in a partition wall 324. The current collector 312 enters the magnetron sputtering chamber 330 and reaches a roller 340 that acts as a rotating substrate support. The roller 340 is grounded. A plurality of sputtering targets 334-1, 334-2, …, and 334-T are circumferentially arranged around a portion of the roller 340, where T is an integer greater than 1.

[0077] After the targets in the plurality of sputtering targets 334-1, 334-2, …, and 334-T sputter amorphous silicon onto the current collector 312, the electrode 344 (the current collector 312 and the sputtered amorphous silicon layer) leaves the magnetron sputtering chamber 330 through an elongated hole 327 (e.g., acting as a vacuum seal) and enters the roll-to-roll chamber 310. The electrode 344 passes over tension rollers 350 and 354, around a roller 358, and is collected on a roller 362.

[0078] The vacuum inside the roll-to-roll chamber 310 can be controlled using a valve 370 and a pump 372 connected to an exhaust system 374. The vacuum inside the magnetron sputtering chamber 330 can be controlled using a valve 380 and a pump 382 connected to an exhaust system 384. A process gas mixture including one or more gases (e.g., argon (Ar)) can be supplied using one or more gas sources, a mass flow controller 292, and / or a valve 294.

[0079] A roughened copper current collector (e.g., foil) is supplied using a roll-to-roll method. A silicon layer is continuously deposited from a plurality of silicon targets on the roughened copper current collector in an argon atmosphere through the magnetron sputtering chamber. After sputtering, the anode electrode is collected on a roller. This method obtains a double-sided anode electrode on the other side of the current collector.

[0080] Now refer to Figure 5A and 5B, showing the anode electrode during charging and discharging. The uneven spherical surface of Si can have more interfaces with the electrolyte (e.g., solid electrolyte) to increase the conduction path of lithium ions, which enhances the power supply capacity of the battery pack. The uneven spherical surface helps to release the stress generated by Si expansion, which enhances the recyclability of the battery pack.

[0081] The anode electrode described herein does not include an ion-insulating binder that enhances power capabilities. In addition, removing the carbon additive eliminates adverse reactions with the electrolyte (e.g., solid electrolyte), which extends the battery cycle life.

[0082] Now refer to Figure 6 and 7 , the anode electrode can be used in battery cells of a battery pack having solid, liquid, and / or gel electrolytes. In Figure 6 , the battery cell of the battery pack includes an anode electrode 540, and the anode electrode 540 includes an amorphous silicon active layer 542 disposed on a roughened current collector 546. The separator 532 includes a polymer separator. The cathode layer 520 includes a cathode active material layer 524 and a cathode current collector 526. A liquid electrolyte 550 (e.g., LiPF6 in carbonate) is used.

[0083] In Figure 7 , the battery cell of the battery pack includes an anode electrode 540, and the anode electrode 540 includes an amorphous silicon active layer 542 disposed on a roughened current collector 546. The separator 562 includes a solid electrolyte. The cathode layer 570 includes a cathode active material layer 574, a solid electrolyte 578, and a cathode current collector 576.

[0084] Now refer to Figure 8 , scanning electron microscope images of a top view and a side view of the anode electrode. Amorphous silicon pillars are shown after being formed on the roughened copper current collector.

[0085] Now refer to Figure 9A and 9B , showing the X-ray diffraction (XRD) pattern and the graph of the Raman spectrum of the anode electrode. In Figure 9A , the deposited silicon film is amorphous and there is no XRD diffraction peak corresponding to Si. In Figure 9B , the Raman spectrum shows a peak at 465 cm -1 , which can be attributed to the transverse optical (TO) mode of amorphous silicon (a-Si).

[0086] Now refer to Figure 10A and 10B , showing the graph of the capacity and the capacity retention percentage of the battery cell including the anode electrode as a function of the cycle. The anode electrode has a load of 3.5 mAh / cm 2 . The cathode electrode has a load of 1.41 mAh / cm2 The load. The cathode active material layer contains NCM523, lithium phosphorus sulfur chloride (LPSCl), and carbon (C) as active materials at a ratio of 5:4:04. In Figure 10A , the rate performance of the anode electrode at 25 °C is shown. In Figure 10B , the cycle performance of the anode electrode at 25 °C is shown. The amorphous silicon anode electrode has good rate performance and an extended cycle life.

[0087] The foregoing description is merely exemplary and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be implemented in a variety of forms. Thus, although the disclosure includes specific examples, the true scope of the disclosure should not be so limited because other modifications will become apparent upon study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be implemented in a different order (or concurrently) without altering the principles of the disclosure. Additionally, although the embodiments are described above as having certain features, any one or more of the features described with respect to any one embodiment of the disclosure may be implemented in and / or combined with the features of any other embodiment, even if not explicitly described in that combination. In other words, the embodiments are not mutually exclusive, and the interchanging of one or more embodiments is still within the scope of the disclosure.

[0088] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "joined," "coupled," "adjacent," "next to," "on top of," "on," "under," and "disposed." Unless explicitly described as "direct," when the relationship between a first element and a second element is described in the foregoing disclosure, the relationship can be a direct relationship in which no other intervening elements exist between the first element and the second element, or an indirect relationship in which one or more intervening elements exist between the first element and the second element (spatially or functionally). The phrase "at least one of A, B, and C" as used herein should be construed to mean a logical (A or B or C) using a non-exclusive logical OR and should not be construed to mean "at least one of A, at least one of B, and at least one of C."

[0089] In the drawings, the direction of the arrow as indicated by the arrow generally shows the information flow (such as data or instructions) of interest in the illustration. For example, when element A and element B exchange various information and the information sent from element A to element B is relevant to the illustration, the arrow can point from element A to element B. Such a unidirectional arrow does not mean that no other information is sent from element B to element A. Additionally, for the information transmitted from element A to element B, element B can send a request for that information or receive an acknowledgment to element A.

Claims

1. A method for manufacturing an anode electrode of a battery cell, comprising: Supplying a roughened anode current collector from a roll-to-roll chamber to a magnetron sputtering chamber; Causing the roughened anode current collector to travel around a roller in the magnetron sputtering chamber; Using T sputtering targets circumferentially arranged around a part of the roller, sputtering an amorphous silicon layer on the roughened anode current collector to form an anode electrode, where T is an integer greater than 1; And Receiving the anode electrode from the magnetron sputtering chamber in the roll-to-roll chamber.

2. The method according to claim 1, wherein the roughened anode current collector is made of a material selected from copper, stainless steel (SS), nickel (Ni), titanium (Ti), and tin (Sb).

3. The method according to claim 1, wherein the roughness (Rz) of the roughened anode current collector is from 0.1 μm to 12 μm.

4. The method according to claim 1, wherein the thickness of the roughened anode current collector is from 0.1 μm to 40 μm.

5. The method according to claim 1, wherein the thickness of the amorphous silicon layer is from 0.1 μm to 20 μm.

6. The method according to claim 1, wherein the amorphous silicon layer includes a plurality of silicon pillars.

7. The method according to claim 6, wherein the diameter of the plurality of silicon pillars is from 0.1 μm to 15 μm.

8. The method according to claim 1, wherein the average areal capacity of the anode electrode is 4 to 30 mAh / cm 2 .

9. The method according to claim 1, wherein the DC bias voltage of the magnetron sputtering chamber is from 100 V to 1000 V.

10. The method according to claim 1, wherein the cathode power of the magnetron sputtering chamber is from 0.5 kW to 30 kW.

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